Screen Printing Adhesive Composition for Uniform Coating
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Solution Overview
Problem
Existing adhesive compositions for semiconductor elements are challenging to apply uniformly over large areas using screen printing, leading to issues with surface smoothness and storage stability in a B-stage, which affects the bonding process and yield of semiconductor devices.
Innovation Solution
A composition comprising 100 parts of epoxy resin, a curing agent with an equivalent ratio of 0.8 to 1.25, a curing promoter, 10 to 150 parts of inorganic filler, 5 to 50 parts of thermoplastic resin particles, and 10 to 100 parts of silicone powder with specific particle sizes, optimized for screen printing to achieve uniform thickness and stability in a B-stage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If existing adhesive compositions are applied by screen printing on large-area substrates, then printing coverage is achieved, but uniformity of coating thickness and surface smoothness deteriorate
Solution Approach 1:
The invention changes the physical and chemical parameters of the adhesive composition by incorporating silicone powder with specific particle size distribution (d50: 1-50 μm, d99: 1/20 to 2/3 of screen opening), thermoplastic resin particles (5-50 parts by weight), and inorganic filler (10-150 parts by weight). These parameter changes modify the rheological properties of the composition, enabling it to maintain uniform flow and filling characteristics during wide-area screen printing, thus achieving both large coverage and high coating uniformity
Solution Approach 2:
The invention creates a composite adhesive composition by combining epoxy resin (100 parts by weight), curing agent (0.8-1.25 equivalent ratio), silicone powder (10-100 parts by weight), inorganic filler (10-150 parts by weight), and thermoplastic resin particles (5-50 parts by weight). This composite structure leverages the complementary properties of each component: epoxy resin provides adhesion, silicone powder controls flow and surface finish, inorganic filler enhances mechanical properties, and thermoplastic resin particles improve B-stage stability. The synergistic combination enables the composition to be successfully applied by screen printing over wide areas while maintaining uniform thickness and smooth surface
2Productivity
If adhesive composition is stored in B-stage for later use, then process flexibility is improved, but curing stability deteriorates
Solution Approach 1:
The invention changes the chemical parameters of the adhesive system by selecting specific curing agents with equivalent ratios of 0.8-1.25 relative to epoxy groups, and adding curing promoters in controlled amounts (0.1-10 parts by weight). These parameter changes optimize the reactivity and stability characteristics of the composition, allowing it to remain stable during B-stage storage while maintaining the capability to cure properly when needed. The controlled stoichiometry and promoter levels prevent premature curing reactions during storage
3Productivity
If screen printing is used for wide area coating, then manufacturing speed is improved, but coating quality deteriorates
Solution Approach 1:
The invention optimizes the rheological parameters of the adhesive composition by incorporating silicone powder with specific particle size distribution and thermoplastic resin particles. These modifications enable the composition to exhibit appropriate viscosity and flow characteristics that are ideal for screen printing processes, allowing the material to flow smoothly through the screen mesh and fill patterns uniformly across large areas, thereby maintaining high coating quality while enabling fast manufacturing
Solution Approach 2:
The composite formulation combining epoxy resin, silicone powder, inorganic filler, and thermoplastic resin particles creates a material with optimized printing properties. The silicone powder acts as a flow control agent, the inorganic filler provides structural support, and the thermoplastic resin particles enhance stability. This composite structure enables the composition to be successfully applied by screen printing over wide areas while maintaining uniform thickness and smooth surface
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The composition enables uniform screen printing over large areas, reduces manufacturing time, and maintains stability in a B-stage, improving the bonding process and yield of semiconductor devices by preventing curing during storage.
Implementation Method 1
silicone powder having a particle size at cumulative 50% (d50), measured by a laser light diffraction method, of from 1 to 50 μm
Implementation Method 2
particle size at cumulative 50% (d50), measured by a laser light diffraction method
Implementation Method 3
an epoxy resin, (B) a curing agent in such an amount that an equivalent ratio of an epoxy-reactive group of the curing agent (B) to the epoxy group of the epoxy resin (A) ranges from 0.8 to 1.25
Implementation Method 4
0.1 to 10 parts by weight, per total 100 parts by weight of the components (A) and (B), of (C) a curing promoter
Data Source
AI summary
An adhesive composition comprising(A) an epoxy resin,(B) a curing agent,(C) a curing promoter,(D) an inorganic filler,(E) particles of a thermoplastic resin which is solid at 25° C., and(F) silicone powder having a particle size at cumulative 50% (d50), measured by a laser light diffraction method, of from 1 to 50 μm.The composition is particularly suitable to be applied by screen printing on a substrate or a silicon wafer.